Systems and methods for controlling additive manufacturing

ABSTRACT

A system is disclosed for use in additively manufacturing a structure. The system may include an additive manufacturing machine, a memory having computer-executable instructions stored thereon, and a processor. The processor may be configured to execute the computer-executable instructions to determine a characteristic of an existing point to be used as an anchor for a path of composite material discharged by the additive manufacturing machine. The processor may also be configured to execute the computer-executable instructions to selectively cause the additive manufacturing machine to discharge the path of composite material with a variable ratio of matrix-to-fiber at the existing point that is based on the characteristic.

RELATED APPLICATIONS

This application is based on and claims the benefit of priority fromUnited States Provisional Application Nos. 62/383,801 filed on Sep. 6,2016; 62/417,709 filed on Nov. 4, 2016; 62/449,899 filed on Jan. 24,2017; 62/459,398 filed on Feb. 15, 2017; and 62/526,448 filed on Jun.29, 2017, the contents of all of which are expressly incorporated hereinby reference.

TECHNICAL FIELD

The present disclosure relates generally to manufacturing controlsystems and, more particularly, to systems and methods for controllingadditive manufacturing.

BACKGROUND

Traditional additive manufacturing is a process of creatingthree-dimensional parts by depositing overlapping layers of materialunder the guided control of a computer. A common form of additivemanufacturing is known as fused deposition modeling (FDM). Using FDM, athermoplastic is passed through and liquified within a heated printhead. The print head is moved in a predefined trajectory (a.k.a., a toolpath) as the material discharges from the print head, such that thematerial is laid down in a particular pattern and shape of overlapping2-dimensional layers. The material, after exiting the print head, coolsand hardens into a final form. A strength of the final form is primarilydue to properties of the particular thermoplastic supplied to the printhead and a 3-dimensional shape formed by the stack of 2-dimensionallayers.

A recently developed improvement over traditional FDM manufacturinginvolves the use of continuous fibers embedded within materialdischarging from the print head. In particular, a matrix is supplied tothe print head and discharged (e.g., extruded and/or pultruded) alongwith one or more continuous fibers also passing through the same head atthe same time. The matrix can be a traditional thermoplastic, a powderedmetal, a liquid matrix (e.g., a UV curable and/or two-part resin), or acombination of any of these and other known matrixes. Upon exiting theprint head, a cure enhancer (e.g., a UV light, an ultrasonic emitter, aheat source, a catalyst supply, etc.) is activated to initiate and/orcomplete curing of the matrix. This curing occurs almost immediately,allowing for unsupported structures to be fabricated in free space. Andwhen fibers, particularly continuous fibers, are embedded within thestructure, a strength of the structure may be multiplied beyond thematrix-dependent strength. An example of this technology is disclosed inU.S. Pat. No. 9,511,543 that issued to Tyler on Dec. 6, 2016 (“the '543patent”).

The disclosed systems and methods are directed to addressing ways ofcontrolling additive manufacturing systems similar to those disclosed inthe '543 patent and/or other systems known in the art.

SUMMARY

In one aspect, the present disclosure is directed to system for use inadditively manufacturing a structure. The system may include an additivemanufacturing machine, a memory having computer-executable instructionsstored thereon, and a processor. The processor may be configured toexecute the instructions to cause the additive manufacturing machinedetermine a characteristic of an existing point to be used as an anchorfor a path of composite material discharged by the additivemanufacturing machine. The processor may also be configured to executethe computer-executable instructions to selectively cause the additivemanufacturing machine to discharge the path of composite material with avariable ratio of matrix-to-fiber at the existing point that is based onthe characteristic.

In another aspect, the present disclosure is directed to a method offabricating a structure with an additive manufacturing machine. Themethod may include determining a characteristic of an existing point tobe used as an anchor for a path of composite material discharged by theadditive manufacturing machine. The method may also include selectivelycausing the additive manufacturing machine to discharge the path ofcomposite material with a variable ratio of matrix-to-fiber at theexisting point that is based on the characteristic.

In yet another aspect, the present disclosure is directed to anon-transitory computer readable medium containing computer-executableprogramming instructions for performing a method of additivelymanufacturing a structure. The method may include causing the additivemanufacturing machine to determining a stability of an existing point tobe used as an anchor for a path of composite material discharged by anadditive manufacturing machine. The method may also include selectivelycausing the additive manufacturing machine to discharge the path ofcomposite material with a variable ratio of matrix-to-fiber at theexisting point that is based on the stability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic illustration of an exemplary disclosed additivemanufacturing machine and a corresponding system that may be used tocontrol the machine;

FIG. 2 is a schematic illustration of the control system of FIG. 1;

FIGS. 3-11 are flowcharts representing exemplary methods that may beimplemented by the control system of FIGS. 1 and 2; and

FIGS. 12 and 13 are diagrammatic illustrations depicting progressionthrough steps in the methods of FIGS. 3-11.

DETAILED DESCRIPTION

FIG. 1 illustrates an exemplary control system (“system”) 10, which maybe used to design, plan, fabricate, and/or analyze a structure 12 havingany desired shape, size, consist, and functionality. System 10 mayinclude, among other things, an additive manufacturing machine(“machine”) 14 and at least one computing device 16 operativelyconnected to machine 14. Machine 14 may be configured to createstructure 12 under the guided control of computing device 16, forexample by way of an additive manufacturing process. Although additivemanufacturing processes utilizing one or more continuous reinforcements(e.g., fibers—F) and one or more curable matrixes (M) will be describedbelow as one example of how structure 12 may be created, it should benoted that other processes known in the art could alternatively beutilized for this purpose and benefit from the disclosed control systemsand methods.

Machine 14 may be comprised of components that are controllable tocreate structure 12, layer-by-layer and/or in free space (e.g., withoutthe bracing of an underlying layer). These components may include, amongother things, a support 18 and any number of heads 20 coupled to andpowered by support 18. In the disclosed embodiment of FIG. 1, support 18is a robotic arm capable of moving head 20 in multiple directions duringfabrication of structure 12. It should be noted that any other type ofsupport (e.g., an overhead gantry, an arm/gantry combination, etc.)capable of moving head 20 in the same or in a different manner couldalso be utilized, if desired.

Each head 20 (only one shown in FIG. 1, for clarity) may be configuredto discharge at least a matrix (e.g., a liquid resin, such as a zerovolatile organic compound resin; a powdered metal; etc.) that iscurable. Exemplary curable matrixes include thermosets, single- ormulti-part epoxy resins, polyester resins, cationic epoxies, acrylatedepoxies, urethanes, esters, thermoplastics, photopolymers, polyepoxides,thiols, alkenes, thiol-enes, and more. In one embodiment, the matrixinside each head 20 may be pressurized, for example by an externaldevice (e.g., an extruder or another type of pump—not shown) that isfluidly connected to head 20 via a corresponding conduit (not shown). Inanother embodiment, however, the pressure may be generated completelyinside of head 20 by a similar type of device. In yet other embodiments,the matrix may be gravity-fed through and/or mixed within head 20. Insome instances, the matrix inside head 20 may need to be kept cooland/or dark to inhibit premature curing; while in other instances, thematrix may need to be kept warm for the same reason. In eithersituation, head 20 may be specially configured (e.g., insulated,chilled, and/or warmed) to provide for these needs.

In some embodiments, the matrix may be mixed with, contain, or otherwisecoat one or more fibers (e.g., individual fibers, tows, rovings,sleeves, ribbons, and/or sheets of material) and, together with thefibers, make up at least a portion (e.g., a wall) of structure 12. Thefibers may be stored within (e.g., on separate internal spools—notshown) or otherwise passed through head 20 (e.g., fed from externalspools). When multiple fibers are simultaneously used, the fibers may beof the same type and have the same diameter and cross-sectional shape(e.g., circular, square, flat, etc.), or of a different type withdifferent diameters and/or cross-sectional shapes. The fibers mayinclude, for example, carbon fibers, vegetable fibers, wood fibers,mineral fibers, glass fibers, metallic wires, optical tubes, etc. Itshould be noted that the term “fiber” is meant to encompass bothstructural and non-structural types of continuous reinforcements thatcan be at least partially encased in the matrix discharging from head20.

The fibers may be exposed to (e.g., coated with) the matrix while thefibers are inside head 20, while the fibers are being passed to head 20,and/or while the fibers are discharging from head 20, as desired. Thematrix, dry fibers, and/or fibers that are already exposed to the matrix(e.g., wetted fibers) may be transported into head 20 in any mannerapparent to one skilled in the art.

Support 18 may move head 20 in a particular trajectory (e.g., atrajectory corresponding to an intended shape, size, and/or function ofstructure 12) at the same time that the matrix-coated fiber(s) dischargefrom head 20, such that continuous paths of matrix-coated fiber(s) areformed along the trajectory. Each path may have any cross-sectionalshape, diameter, and/or fiber and matrix density, and the fibers may beradially dispersed with the matrix, located at a general center thereof,or located only at a periphery.

One or more cure enhancers (e.g., a UV light, an ultrasonic emitter, alaser, a heater, a catalyst dispenser, etc.) 22 may be mounted proximate(e.g., within or on) head 20 and configured to enhance a cure rateand/or quality of the matrix as it is discharged from head 20. Cureenhancer 22 may be regulated to selectively expose surfaces of structure12 to energy (e.g., to UV light, electromagnetic radiation, vibrations,heat, a chemical catalyst or hardener, etc.) during the formation ofstructure 12. The energy may increase a rate of chemical reactionoccurring within the matrix, sinter the matrix, harden the matrix, orotherwise cause the matrix to cure as it discharges from head 20. In thedepicted embodiments, cure enhancer 22 includes multiple LEDs that areequally distributed about a center axis of head 20. However, it iscontemplated that any number of LEDs or other energy sources couldalternatively be utilized for the disclosed purposes and/or arranged inanother manner (e.g., unequally distributed, arranged in a row, etc.).For example, cure enhancers 22 could be located on an arm (not shown)that trails behind head 20, if desired. The amount of energy produced bycure enhancer 22 may be sufficient to cure the matrix before structure12 axially grows more than a predetermined length away from head 20. Inone embodiment, structure 12 is completely cured before the axial growthlength becomes equal to an external diameter of the matrix-coatedreinforcement.

In the embodiment of FIG. 1, head 20 is modular. For example, head 20may include a matrix reservoir 26 and a nozzle module 24 removablyconnected to matrix reservoir 26 (e.g., via one or more threadedfasteners, clasps, or other hardware—not shown). In this example, nozzlemodule 24 is a single-track nozzle module 24A configured to dischargecomposite material having a generally circular cross-section. Theconfiguration of head 20, however, may allow nozzle module 24A to beswapped out for another nozzle module (e.g., module 24B, module 24C,etc.) that discharges composite material having a different shape (e.g.,a tubular cross-section, a ribbon or sheet cross-section, etc.). Duringthis swap-out, matrix reservoir 26 may remain connected to support 18,and few (if any) modifications of matrix reservoir 26 may be required.

In one embodiment, nozzle module 24 may also or alternatively beselectively swapped out for a machining module 28. For example, a modulehaving one or more finishing tools (e.g., drill bits, milling bits,blades, grinders, painters, coaters, cleaning devices, etc.) may beselectively attached to matrix reservoir 26 (or directly to an end ofsupport 18), if desired. This configuration may allow for a greaterrange of structures 14 to be fabricated by machine 14.

In some embodiments, cure enhancer(s) 22 may be mounted to a lowersurface of nozzle module 24. With this configuration, cure enhancer(s)22 may be located around a nozzle tip in a configuration that best suitsthe shape, size, and/or type of material discharging from nozzle module24. In the disclosed embodiment, cure enhancer(s) 22 are mounted at anangle relative to an axis of nozzle module 24, such that energy fromcure enhancer(s) 22 is directed toward the material discharging fromnozzle module 24. An energy blocker 30 and/or optics 31 may be used insome applications, to selectively block, focus, and/or aim the energyfrom cure enhancers 22 at an outlet of nozzle module 24. This may affecta cure rate of and/or cure location on the material discharging fromnozzle module 24. It is contemplated that energy blocker 30 and/oroptics 31 may be adjustable, if desired (e.g., manually adjustable via aset screw—not shown, or automatically adjustable via an actuator—notshown).

The matrix and fiber(s) may be discharged from head 20 via at least twodifferent modes of operation. In a first mode of operation, the matrixand fiber(s) are extruded (e.g., pushed under pressure and/or mechanicalforce) from head 20, as head 20 is moved by support 18 to create theshape of structure 12. In a second mode of operation, at least thefiber(s) are pulled from head 20, such that tensile stresses are createdin the fiber(s) during discharge that remain after curing of the matrix.In this mode of operation, the matrix may cling to the fiber(s) andthereby also be pulled from head 20 along with the fiber(s), and/or thematrix may be discharged from head 20 under pressure along with thepulled fiber(s). In the second mode of operation, where the fiber(s) arebeing pulled from head 20, the resulting residual tension in thefiber(s) may increase a strength of structure 12, while also allowingfor a greater length of unsupported material to have a straightertrajectory (i.e., the residual tension may act against the force ofgravity to provide free-standing support for structure 12).

The fiber(s) may be pulled from head 20 as a result of head 20 movingaway from an anchor point 32. For example, at the start ofstructure-formation, a length of matrix-impregnated fiber(s) may bepulled and/or pushed from head 20, deposited onto anchor point 32, andcured, such that the discharged material adheres to anchor point 32.Thereafter, head 20 may be moved away from anchor point 32, and therelative movement may cause the fiber(s) to be pulled from head 20. Itshould be noted that the movement of fiber(s) through head 20 could beassisted (e.g., via internal feed mechanisms), if desired. However, thedischarge rate of fiber(s) from head 20 may primarily be the result ofrelative movement between head 20 and anchor point 32, such that tensionis created within the fiber(s). It is contemplated that anchor point 32could be moved away from head 20 instead of or in addition to head 20being moved away from anchor point 32.

As will be described in more detail below, it has been determined that atension vector associated with each continuous fiber discharged by head20 may contribute to a characteristic (e.g., a stiffness and/orstrength) of structure 12. For example, a stiffness and/or strength ofstructure 12 may be generally greater in an axial direction of eachfiber, and greater by an amount related to the level of residual tensionin that fiber. Accordingly, during a pre-processing (e.g., design) phaseand/or processing phase of fabricating structure 12, care may be takento provide a desired amount, size, and/or shape of particular fibers inalignment with particular trajectories and/or to generate desiredtension levels within each of the fibers prior to and/or during curing,such that structure 12 performs according to required specifications.

Any number of separate computing devices 16 may be used to design and/orcontrol the placement and residual tension of fibers within structure 12and/or to analyze performance characteristics (e.g., stiffness andstrength, and/or other characteristics such as continuity) of structure12 before and/or after formation. Computing device 16 may include, amongother things, a display 34, one or more processors 36, any number ofinput/output (“I/O”) devices 38, any number of peripherals 40, and oneor more memories 42 for storing programs 44 and data 46. Programs 44 mayinclude, for example, any number of design and/or printing apps 48 andan operating system 50.

Display 34 of computing device 16 may include a liquid crystal display(LCD), a light emitting diode (LED) screen, an organic light emittingdiode (OLED) screen, and/or another known display device. Display 34 maybe used for presentation of data under the control of processor 36.

Processor 36 may be a single or multi-core processor configured withvirtual processing technologies, and use logic to simultaneously executeand control any number of operations. Processor 36 may be configured toimplement virtual machine or other known technologies to execute,control, run, manipulate, and store any number of software modules,applications, programs, etc. In addition, in some embodiments, processor36 may include one or more specialized hardware, software, and/orfirmware modules (not shown) specially configured with particularcircuitry, instructions, algorithms, and/or data to perform functions ofthe disclosed methods. It is appreciated that other types of processorarrangements could be implemented that provide for the capabilitiesdisclosed herein.

Memory 42 can be a volatile or non-volatile, magnetic, semiconductor,tape, optical, removable, non-removable, or other type of storage deviceor tangible and/or non-transitory computer-readable medium that storesone or more executable programs 44, such as analysis and/or printingapps 48 and operating system 50. Common forms of non-transitory mediainclude, for example, a flash drive, a flexible disk, a hard disk, asolid state drive, magnetic tape or other magnetic data storage medium,a CD-ROM or other optical data storage medium, any physical medium withpatterns of holes, a RAM, a PROM, an EPROM, a FLASH-EPROM or other flashmemory, NVRAM, a cache, a register or other memory chip or cartridge,and networked versions of the same.

Memory 42 may store instructions that enable processor 36 to execute oneor more applications, such as design and/or fabrication apps 48,operating system 50, and any other type of application or software knownto be available on computer systems. Alternatively or additionally, theinstructions, application programs, etc. can be stored in an internaland/or external database (e.g., a cloud storage system—not shown) thatis in direct communication with computing device 16, such as one or moredatabases or memories accessible via one or more networks (not shown).Memory 42 can include one or more memory devices that store data andinstructions used to perform one or more features of the disclosedembodiments. Memory 42 can also include any combination of one or moredatabases controlled by memory controller devices (e.g., servers, etc.)or software, such as document management systems, Microsoft SQLdatabases, SharePoint databases, Oracle™ databases, Sybase™ databases,or other relational databases.

In some embodiments, computing device 16 is communicatively connected toone or more remote memory devices (e.g., remote databases—not shown)through a network (not shown). The remote memory devices can beconfigured to store information that computing device 16 can accessand/or manage. By way of example, the remote memory devices could bedocument management systems, Microsoft SQL database, SharePointdatabases, Oracle™ databases, Sybase™ databases, Cassandra, HBase, orother relational or non-relational databases or regular files. Systemsand methods consistent with disclosed embodiments, however, are notlimited to separate databases or even to the use of a database.

Programs 44 may include one or more software or firmware modules causingprocessor 36 to perform one or more functions of the disclosedembodiments. Moreover, processor 36 can execute one or more programslocated remotely from computing device 16. For example, computing device16 can access one or more remote programs that, when executed, performfunctions related to disclosed embodiments. In some embodiments,programs 44 stored in memory 42 and executed by processor 36 can includeone or more of design, fabrication, and/or analysis apps 48 andoperating system 50. Apps 48 may cause processor 36 to perform one ormore functions of the disclosed methods.

Operating system 50 may perform known operating system functions whenexecuted by one or more processors such as processor 36. By way ofexample, operating system 50 may include Microsoft Windows™, Unix™,Linux™, OSX™, and IOS™ operating systems, Android™ operating systems, oranother type of operating system 50. Accordingly, disclosed embodimentscan operate and function with computer systems running any type ofoperating system 50.

I/O devices 38 may include one or more interfaces for receiving signalsor input from a user and/or machine 14, and for providing signals oroutput to machine 14 that allow structure 12 to be printed. For example,computing device 16 can include interface components for interfacingwith one or more input devices, such as one or more keyboards, mousedevices, and the like, which enable computing device 16 to receive inputfrom a user.

Peripheral device(s) 40 may be standalone devices or devices that areembedded within or otherwise associated with machine 14 and used duringfabrication of structure 12. As shown in FIG. 2, peripherals 40 canembody input devices (e.g., one or more sensors, such as tensionsensors, position sensors, pressure sensors, temperature sensors, flowsensors, continuity sensors, humidity sensors, rotary encoders, andother sensors known in the art) 40A and/or output devices (e.g., one ormore actuators, such as a matrix supply, a fiber supply, a cooling fan,a pump, cure enhancer 22, a positioning motor, a cutter, a splicer, aweaving mechanism, a fiber guide, a mixer, a feed roller, a frictiontensioner, etc.) 40B. In some embodiments, peripherals 40 may,themselves, include one or more processors, a memory, and/or atransceiver. When peripheral device(s) 40 are equipped with a dedicatedprocessor and memory, the dedicated processor may be configured toexecute instructions stored on the memory to receive commands fromprocessor 36 associated with video, audio, other sensory data, controldata, location data, etc., including capture commands, processingcommands, motion commands, and/or transmission commands. The transceivermay include a wired or wireless communication device capable oftransmitting data to or from one or more other components in system 10.In some embodiments, the transceiver can receive data from processor 36,including instructions for sensor and/or actuator activation and for thetransmission of data via the transceiver. In response to the receivedinstructions, the transceiver can packetize and transmit data betweenprocessor 36 and the other components.

Design, fabrication, and/or analysis apps 48 may cause computing device16 to perform methods related to generating, receiving, processing,analyzing, storing, and/or transmitting data in association withoperation of machine 14 and corresponding design/fabrication/analysis ofstructure 12. For example, apps 48 may be able to configure computingdevice 16 to perform operations including: displaying a graphical userinterface (GUI) on display 34 for receiving design/control instructionsand information from the operator of machine 14; capturing sensory dataassociated with machine 14 (e.g., via peripherals 40A); receivinginstructions via I/O devices 38 and/or the user interface regardingspecifications, desired characteristics, and/or desired performance ofstructure 12; processing the control instructions; generating one ormore possible designs of and/or plans for fabricating structure 12;analyzing and/or optimizing the designs and/or plans; providingrecommendations of one or more designs and/or plans; controlling machine14 to fabricate a recommended and/or selected design via a recommendedand/or selected plan; analyzing the fabrication; and/or providingfeedback and adjustments to machine 14 for improving futurefabrications.

FIGS. 3-11 are flowcharts depicting exemplary methods that may beimplemented by computing device 16 during design, fabrication, and/oranalysis of structure 12 by machine 14. FIGS. 3-11 will be discussed indetail in the following section to further illustrate the disclosedconcepts.

INDUSTRIAL APPLICABILITY

The disclosed systems may be used to continuously manufacture compositestructures having any desired cross-sectional shape, length, density,stiffness, strength, and/or other characteristic. The compositestructures may include any number of different reinforcements of thesame or different types, diameters, shapes, configurations, andconsists, and/or any number of different matrixes. Operation of system10 will now be described in detail, with reference to the flowcharts ofFIGS. 3-11.

As can be seen in the flowchart of FIG. 3, the creation of structure 12may generally be divided into four different phases, including:pre-processing, processing, post-processing, and analysis. Thepre-processing phase may generally be associated with defining ofstructure 12. The processing phase may generally be associated withforming of at least a base portion of structure 12. The post-processingphase may generally be associated with final finishing of the baseportion of structure 12. The analysis phase may generally be associatedwith comparing of the pre-processing definition of structure 12 withobservations of a physical embodiment of structure 12, as well asiterative adjusting of the previous phase(s) based on the comparison.

The pre-processing phase of structure creation may begin with receipt byprocessor 36 (e.g., via I/O device(s) 38) of specifications from a userof system 10 (Step 300). These specifications may include, among otherthings, a physical envelope of structure 12 (e.g., an exterior surfacedefinition of structure 12 and/or a definition of a space in whichstructure 12 is to reside and function), expected operating conditions(e.g., force loading, deflection loading, vibratory loading, thermalloading, environmental loading, etc.), desired characteristics (e.g.,hardness, weight, buoyancy, etc.), and/or desired performance (e.g.,minimum values, maximum values, and/or acceptable ranges for particularparameters, such as conductance, stiffness, strength, etc.). Forexample, a user of system 10 may input a mating interface definitionthat structure 12 should comply with in an associated assembly (e.g., ashape, size, location, and orientation of an end of a keyed axle onwhich the turbine wheel depicted in FIG. 1 should rotate), a maximumvolume (e.g., axial and/or radial size limitations) that can be occupiedby structure 12, levels of forces expected to pass through structure 12in particular directions (e.g., a flowrate and density of gasses passingradially into and axially out of the turbine wheel and/or a resistivetorque expected within the axle), and how structure 12 should respond tothe forces (e.g., an amount of torque that should be generated withinthe turbine wheel by the gases and/or a maximum amount of stiffnessand/or deflection allowed within each vane of the turbine wheel due toapplied torques).

The specifications received at step 300 may then be fed into one or moreCAD Modules (Step 302), which will be discussed in more detail below.The CAD Module(s) may return one or more possible designs (e.g., shapes,materials, fiber trajectories, fiber tension levels, densities, etc.)for structure 12 based on the received specifications, as long as one ormore designs are possible for the given specifications. If computingdevice 16 determines that an error exists in association with thedesign(s) (Step 304), the error may be displayed to a user of system 10,along with a prompt for modification of the provided specifications(Step 306). Control may then return from Step 306 to Step 300.

Once any possible designs for structure 12 have been successfullyreturned by the CAD Module(s), computing device 16 may receive from theuser a Print Information Packet (“PIP”) (Step 308). The PIP may containvalues for system 10 that can affect fabrication of structure 12. Thesevalues may include, for example, a current configuration of machine 14(e.g., a type and/or condition of a particular nozzle module 24connected to and/or available for use with machine 14), a type and/oramount of material (e.g., matrix and/or fiber) currently loaded intomachine 14, a type and/or capability of support 18 connected to head 20,etc. For example, the user may indicate that nozzle module 24A iscurrently connected to machine 14, that 50 m of 4,000-tow carbon fiberis available and loaded into head 20, that matrix reservoir 26 issupplied with 6.2 L of a particular UV curable resin, and that support18 is a 6-axis robotic arm having a particular range of motion, force,and/or speed. It is contemplated that, in some embodiments, thisinformation may be automatically detectable and/or trackable bycomputing device 16 (e.g., via one or more peripherals 40), if desired.In these embodiments, Step 308 may be omitted.

The PIP and the one or more possible designs may be delivered to aPathing Module (Step 310), which will be discussed in more detail below.The Pathing Module(s) may return one or more possible plans (e.g., setsof sequential tool paths) for fabricating the one or more design(s) ofstructure 12 based on the received PIP, as long as one or more plans arepossible for the given PIP. If computing device 16 determines an errorexists in association with the plan(s) (Step 312), the error may bedisplayed to the user of system 10, along with a prompt for modificationof the provided PIP (Step 314). Control may then return from Step 314 toStep 308.

At any time during completion of Steps 302-312, one or more of thepossible designs and/or plans generated by the CAD and/or PathingModules may be selected for use in fabricating structure 12 (Step 315).This selection may be manually completed by the user of system 10 (e.g.,via I/O device(s) 38) or automatically by processor 36 (e.g., based oninstructions stored in memory 42, based on a priority of thespecifications received at Step 300, based on analysis of the design(s)and/or plan(s), and/or using one or more available optimizationalgorithms of apps 48). When a particular design is selected prior toStep 310, Step 310 may be completed with respect to only the selecteddesign. In some instances, each possible design may need to be pairedwith one or more plans prior to optimization and/or selection.

After completion of Step 314, control may proceed to a System CheckModule (Step 316), which may be responsible for checking operationalreadiness of system 10 (e.g., via peripherals 40). The System CheckModule will be described in more detail below. If processor 36determines an error exists in association with the system check (Step318), the error may be displayed to the user of system 10, along with aprompt for modification of system parameters (Step 320). Control maythen return from Step 320 to Step 316.

Once the readiness check of system 10 has been completed successfully,the selected design of structure 12, selected fabrication plan, and thePIP, may be provided to a Setup Module (Step 324) and the ProcessingPhase of structure fabrication may begin. The Setup Module may beresponsible for setting up machine 14 to follow the selected plan andproduce the selected design of structure 12 within the parameters of thePIP. The Setup Module will be described in more detail below.

If processor 36 determines (via the Pathing Module) that any temporarybracing or support is required, processor 36 may generate commandsdirected to machine 14 that cause machine 14 to fabricate the temporarybracing or support (Step 326) after machine 14 has been properly set up(e.g., after completion of step 324). For example, processor 36 maygenerate commands that cause at least a first output device ofperipherals 40B (e.g., a fiber supply) to inhibit discharge of fibersfrom head 20; cause at least a second output device of peripherals 40B(e.g., a matrix supply) to allow discharge of only a temporary matrix(e.g., a matrix that can be rinsed away with water, air, or anothersolvent); cause at least a third output device of peripherals 40B (e.g.,positioning motors associated with support 18) to move head 20 to aposition corresponding with the required bracing or support location;and cause at least a fourth output device of peripherals 40B (e.g., cureenhancer 22) to activate and cure the temporary matrix discharging fromhead 20 during the movement of head 20 within an envelope of thetemporary bracing or support.

Control may then proceed to an Anchor Module (Step 328), which mayregulate anchoring of matrix-coated fibers to anchor point 32 (referringto FIG. 1) in preparation for discharge of a next path of material underthe control of a Discharge Module (Step 330). Both of the Anchor andDischarge Modules will be explained in more detail below, along with aQuality Control Module that may implement a sub-routine duringcompletion of each tool path to ensure that the matrix-coated fibershave been discharged according to the plan (Step 332).

Processor 36 may be configured to continuously monitor the discharge ofmaterial from head 20, not only for quality control purposes, but alsoto track the progress according to the selected plan. This monitoringmay be completed, for example, based on signals received from one ormore input devices of peripherals 40A. Processor 36 may determine when acurrent tool path in the plan is complete (e.g., by comparing a currentposition of head 20 to an end position in the tool path—Step 334), andthereafter determine if severing and/or splicing of any fibers extendingfrom head 20 is required (Step 336). Severing of the fibers may berequired when a next tool path in the plan for structure 12 does notstart at the termination point of the current tool path. For example, ifhead 20 must be moved prior to further discharge of additional material,processor 36 may determine that severing is required. Splicing of thefibers may be required if the fibers in the next tool path are differentfrom the fibers in the current tool path.

When severing and/or splicing is required, control may proceed to aSevering/Splicing Module (Step 338), after which processor 36 maydetermine if any additional tool paths are required to completefabrication of structure 12 (Step 340). If no severing or splicing isrequired, control may advance directly from Step 336 to Step 340.Processor 36 may determine that additional tool paths are required, forexample, based on comparison of any completed tool paths with a numberand/or identification of tool paths included within the fabrication planfor structure 12. When additional tool paths are required, control mayreturn from Step 340 to Step 324. Otherwise, the Processing Phase may beconsidered complete.

The Post-Processing Phase may begin with processor 36 determining if theplan for fabrication of structure 12 calls for any post-processingactivities (e.g., coating, sintering, machining, templating, electronicspick/place, etc.). When any of these activities are specified in theplan for fabrication of structure 12, control may advance from Step 342to Step 344, where the activities are then completed. Whenpost-processing activities are not required or after any requiredactivities have been completed, the Analysis Phase may begin.

The Analysis Phase may begin with testing of the just-fabricatedstructure 12 (Step 346). The testing may correspond with thespecifications received at Step 300 and include, for example, hardnesstesting, strain testing, continuity testing, weight testing, buoyancytesting, etc. Results from the testing may then be compared to thespecifications (Step 348) to determine if structure 12 has satisfied thecorresponding requirements. If the requirements have not been adequatelysatisfied, structure 12 may be rejected (Step 350), the CAD Module maybe updated (Step 352), and control may return to Step 302. Updating ofthe CAD Module may include, among other things, adjustments of data 46and/or associated maps/algorithms (e.g., adjustments of hardnessrelationships, tensile relationships, density relationships,material-type relationships, processing parameter relationships, etc.)that are stored within memory 42 and relied upon by apps 48 to generatethe possible designs, to generate the possible plans, and/or to optimizethe designs and plans. When the requirements of structure 12 have beenproven satisfied, structure 12 may be accepted and the process may berepeated to fabricate another unit of structure 12.

Returning to the CAD Module shown in FIG. 4, processor 36 may generatethe possible design(s) of structure 12 in multiple different steps, someof which may be performed in any order. One of these steps (i.e., Step400) may include, for example, generation of boundaries (e.g., exteriorsurfaces) of structure 12 based, at least in part, on envelopelimitations provided by the user at Step 300 (referring to FIG. 3). Inthe provided example of the turbine wheel (referring to FIG. 1), theenvelope limitations may include bounding axial planes marking limitsbeyond which the turbine wheel may not extend in an axial direction; aninner radial limit (e.g., the axle interface described above); and anouter radial limit (e.g., the inner surface of an associated shroud,including space for a desired annular airflow gap). Processor 36 maythen generate virtual surfaces at these boundary limitations, and createiterative designs having virtual surfaces spaced at decreasingincremental offsets from these limitations. It is also contemplated thatthe virtual surfaces could alternatively be created at innermostboundary limits, and iteratively moved outward by increasing incrementaloffsets, if desired. Detailed features of structure 12 (e.g., vanes ofthe turbine wheel) may then be formed within these virtual surfaces, andnumbers of and spacing between the features may be incrementally variedto produce a range of different spatial layouts. For example, theturbine wheel could be designed to have a greater or lesser number ofthicker or thinner vanes, with larger or smaller radial gapstherebetween.

In conjunction with the different spatial layouts of structure 12created at Step 400, processor 36 may determine any number of differentmatrixes, fibers, and/or fiber densities that could be used to fabricatethe different designs while still providing the characteristicsspecified by the user at Step 300. For example, for any given one of thespatial layouts generated at Step 400, there may be one or morematrixes, one or more fibers, and/or one or more densities that allowthe given spatial layout to be within a weight guideline, provide adesired level of electrical insulation or conductivity, provide adesired buoyancy, etc. These windows of matrixes, fibers, and/ordensities may be paired with each of the different spatial layouts.

Processor 36 may then determine a trajectory of one or more of the fibertypes that were previously determined to be available for each spatiallayout, as well as a level of residual tension that should be presentwithin each fiber (Step 420). This determination may be made, forexample, based at least partially on the loading conditions and/or thedesired performance specified at Step 300. For example, in order toprovide a desired level of stiffness, strength, vibratory response,etc., within the vanes of the turbine wheel, a particular number/densityof first fibers may need to be provided with a first tensile vector at afirst location in order for the desired performance to be provided;while a particular number/density of second fibers may need to beprovided with a second tensile vector at a second location in order forthe same performance to be provided. These parameters may be determinedby processor 36 for each matrix/fiber combination within each of thepossible spatial layouts. The fiber parameters may be determined, forexample, via iterative use of finite element analysis algorithms (e.g.,via apps 48).

In some instances, the level of tension within particular fibers may beless important. In these instances, the tensile vector may still specifya positive value that is just above a minimum level (e.g., just abovezero).

In some embodiments, one or more optimization routines may then beimplemented by processor 36 to narrow down the range of different designcombinations and/or to provide a recommendation to the user of aparticular design (Step 430). The optimization may be performed, forexample, based on a user-defined priority of the given specifications.For example, in some instances, a footprint of structure 12 may be mostimportant, followed by weight, followed by performance, followed bycost; while in other instances, cost may be more important than thefootprint, and weight the least important. Processor 36 may beconfigured to selectively implement the optimization routines (e.g.,using apps 48), and provide the results to the user for final selectionof a particular design (e.g., via display 34). In some instances,processor 36 may automatically select the design that best fits therequired specifications.

In some instances, it may not be possible to generate a design thatsatisfies all of the user-specified requirements. In these instances,processor 36 may return the error subsequently shown on display 34(referring to FIG. 1) at Step 306 (referring to FIG. 3). It is alsocontemplated that processor 36 may not be able to automatically designall features of structure 12. For example, the user may need to generateand/or refine some features manually. It is further contemplated thatprocessor 36 may not implement any kind ofdesign/selection/optimization/recommendation process and that the PIPmay simply include all information required to produce a specific designof structure 12.

Once a particular design has been selected (e.g., manually selected bythe user via I/O devices 38 or automatically selected by processor 36),processor 36 may determine a particular setup of machine 14 required tofabricate the selected design. For example, processor 36 may determine aminimum quantity of fiber (e.g., at least 25% more than specified forthe design) required to produce the design; a minimum volume of matrix(e.g., at least 25% more than specified for the design); a particularnozzle module(s) 24 that must be connected to head 20 (e.g., based on anumber of fibers in a particular reinforcement, a fiber diameter, afiber shape, a fiber type, a matrix viscosity, a matrix flow rate,etc.); a required arrangement (e.g., number, orientation, intensity,etc.) of cure enhancer(s) 20; required use of energy blocker 30 and/oroptics 31; required ranges of motion, speed, and/or force from support18; etc. This information (which can be packaged together as basicoperational information—“BOI”) may be later fed into the Setup Module atStep 324 (referring to FIG. 3).

Returning to the Pathing Module shown in FIG. 5, processor 36 maygenerate any number of possible plans for fabricating the selecteddesign of structure 12. Each plan may include, among other things, anumber of individual tool paths that together form structure 12, as wellas a sequence and/or timing of each path. Processor 36 follow anoptimization and/or selection process (e.g., based on time, materialusage, cost, appearance, etc.) similar to that described above in regardto the possible design, in order to provide a recommendation and/or toautomatically select one of the plans for execution.

To generate each plan, processor 36 may begin by executing the PathingModule shown in FIG. 5. For example, processor 36 may determine ifstructure 12 is a performance-critical part (Step 500). In particular,some structures 12 may not have strength, stiffness, continuity, and/orother similar specifications. In these embodiments, the location offibers and/or the way in which structure 12 is fabricated may be lessimportant and structure 12 may be considered not to be aperformance-critical part. In other embodiments, specifications forstrength, stiffness, continuity, etc. may exist, but the values may belower than established thresholds values (e.g., values associated withselected matrixes, fibers, densities, and/or shapes), also allowingprocessor 36 to consider the corresponding structure not aperformance-critical part. In these embodiments, processor 36 may slicea virtual model of structure 12 into any number of sequentiallyexecutable planes having any orientation that promotes fabricationefficiency (Step 502). For example, processor 36 may slice the virtualmodel into horizontal, parallel, and overlapping layers. For thepurposes of this disclosure, the term “sequentially executable planes”may refer to a set of planes or layers of structure 12 that can befabricated in sequence without inhibiting access to another planefurther down in the sequence.

For each of these layers (e.g., P₁—see FIG. 13), processor 36 maygenerate a set of critical points (e.g., CP₁₋₁, CP₁₋₂; CP₂₋₁, CP₂₋₂,CP₂₋₃, CP₂₋₄—see FIG. 13) based on the envelope (e.g., required shapeand/or size) of structure 12 and a specified tolerance zone for theenvelope (Step 504). The points included within the set may beconsidered critical when material must pass through the points (and in aparticular trajectory between the points) in order for the requiredshape of structure 12 to be fabricated, within the specified tolerancezone. For example, a straight tool path of material (e.g., TP₁—see FIG.13) within structure 12 along a surface wall or edge may require twocritical points (e.g., a starting point and an ending point), while acurved tool path (e.g., TP₂—see FIG. 13) may require three or morecritical points. In general, tighter tolerances may require a highernumber of critical points to define the shape of structure 12.

Once the set of points within each layer of structure 12 has beengenerated, processor 36 may generate one or more tool paths that connectthe different points in the set (Step 506). In general, a tool path maybe considered a continuous track between points that does not requirenozzle module 24 to move without discharging material (e.g., toreposition for a next discharging event). In one embodiment, the toolpath(s) may be organized in a middle-out arrangement. For example, thetool path(s) may begin at a general center of a given plane, move in afirst direction until the tool path passes through a first criticalpoint at an edge or surface of structure 12, turn through a specifiedangle (e.g., about 90°) in a specified direction (e.g., clockwise), andmove in a second direction until the tool path passes through a secondcritical point at another edge or surface of structure 12. This processmay be repeated, until all critical points in a given plane have beenconsumed by the associated tool paths of that plane. In some instances,rather than linear segments joined to each other at 90° corners, thepaths could instead or additionally include arcuate segments arranged inan outwardly spiraling pattern. Each time that nozzle module 24 isrequired to move without discharging material, the current tool path maybe terminated and a new path initiated.

Each tool path or segment of a tool path may be located adjacent anothertool path or segment of the same tool path, and radially spaced fromeach other by a specified distance. This distance may be, for example, afunction of fiber size (e.g., diameter or other cross-sectionaldistance), a function of machine resolution (e.g., a minimum step in theradial direction), and/or a constant value determined through labtesting. The distance may be measured, for example, as a straight linebetween centers of the adjacent tool paths.

Returning to Step 500, when processor 36 determines that the structure12 to be fabricated is a performance-critical part (e.g., based onanticipated loading of structure 12 and/or performance specificationsfor given loading conditions), processor 36 may implement a slicingtechnique different from the one described above. For example, processor36 may slice structure 12 into one or more sequentially executableplanes (e.g., P₁, P₂, P₃, etc.—see FIG. 12) that are not necessarilyparallel to each other, horizontal, or overlapping. Instead, processor36 may slice structure 12 into one or more planes that are each formedby two or more of the tension vectors (e.g., T₁, T₂, etc.—see FIG. 12)described above (e.g., by adjacent tension vectors and/or by tensionvectors that are generally parallel with each other and proximate withina threshold distance) (Step 508).

In some situations, the sequentially executable planes generated at Step508 may not be within the capabilities of machine 14 to fabricate. Forexample, the planes may be at angles not achievable by support 18 and/orwithin spaces too small for nozzle module 24. Accordingly, processor 36may be configured to compare parameters of each plane generated at Step508 with known capabilities of machine 14 (Step 510), and to reject anyplanes that exceed the capabilities of machine 14. For example, controlmay return from Step 510 to Step 508 for generation of replacementplanes, when processor 36 determines that any of the previouslygenerated planes fall outside the capabilities of machine 14. FollowingStep 510, a Step 512 that is substantially identical to Step 504 may becompleted.

Once a set of critical points has been generated for each plane or layerof structure 12, processor 36 may generate one or more tool paths foreach plane that consumes the critical points (Step 514). In contrast toStep 506 described above, processor 36 may generate the tool path(s) atStep 514 based not primarily on efficiency, but more on the tensionvectors described above. In particular, the tension vectors maygenerally lie along the axes of fibers contained within each path and/orbe resultants of two or more co-located fibers (e.g., fibers within thesame path, fibers within adjacent tool paths, fibers within the sameplane, and/or fibers within adjacent planes). In this way, the requiredtension vectors may be created by the tool paths generated at Step 512.In most embodiments, the tool paths generated at Step 514 will notfollow the middle-out approach described above.

After creation of the tool paths for a given plane or layer of structure12 (e.g., after completion of Steps 506 and/or 514), processor 36 maydetermine if all of the critical points in that plane have been consumed(e.g., included within a path) (Step 516). In particular, there may beplanes that contain one or more outlier critical points (e.g.,CP_(O)—see FIG. 13) that are difficult to include in an existing toolpath that extends through another non-outlier critical point. In thesesituations, additional tool paths (TP_(O)—see FIG. 13) must be generatedthat consume the outlier critical points and connect these points to therest of structure 12. To generate these additional tool paths, processor36 must first determine if fiber cutting is permissible (e.g., based onperformance specifications, continuity specifications, etc.) (Step 518).If cutting is not permissible, nozzle module 24 may be unable to movefrom the end of an existing tool path to the start of the additionaltool path, without discharging material during the move. In thissituation, processor 36 may cause an error message to be shown ondisplay 34, and the current fabrication process may end.

However, when processor 36 determines that cutting is permissible,processor 36 may generate cut-code for the end of the existing toolpath, generate anchor-code for the start of the additional tool path,and generate movement-code for transitioning between the existing toolpath and the additional tool path (Step 522). The additional path may beanchored (e.g., start at) at a location nearest the outlier criticalpoint that is on the existing path. It should be noted that processor 36may also generate cut-, anchor-, and movement-code during transitioningbetween existing paths (i.e., paths that do not include outlier criticalpoints) at Step 522.

Returning to Step 516, when processor 36 determines that no criticalpoints were missed during path generation, processor 36 may generatecut-code for the end of a final path within a given plane or layer ofstructure 12, generate anchor-code for the start of a first path in anew plane, and generate movement-code for transitioning between thefinal path and the first path (Step 526).

Once all paths in each plane or layer of structure 12 have beengenerated, processor 36 may assign print speeds and cure parameters(e.g., operational parameters of cure enhancers 22, such as angle,intensity, wavelength, etc.) for each path, for each segment of eachpath (Step 524), and/or for each transition movement described above.These assignments may be made, for example, based on a requiredmatrix-to-fiber ratio, a required density, a required cure amount orhardness specifications for structure 12, and/or a required fabricationtime.

After generation of all required paths, processor 36 may determine ifany of the paths are to be formed in free space (Step 528). For thepurposes of this disclosure, a path is considered to be formed in freespace when at least a portion of the path does not lie directly on topof (e.g., overlap) a previously discharged path of material. When a pathis formed in free space, in some situations, the path may need to bebraced or supported to inhibit deviation from a desired location duringcuring.

When processor 36 determines that a path is to be formed in free space,processor 36 may determine if that path includes curvature having aradius less than a minimum threshold (Step 530). It has been determinedthat gentle curves within a given path (e.g., curves having a radiusgreater than the minimum threshold) are less prone to deviation fromtheir desired locations during curing and/or during subsequent movementof nozzle module 24 (e.g., when fibers are pulled by nozzle module 24moving away from the unsupported segment of the free-space path). Inthese situations, processor 36 may not always generate code forfabrication of bracing or supports. Instead, processor 36 may determineif the unsupported segment of the curving path is to be compacted (Step532), and then estimate if such a compaction could cause undesireddeviations. For example, when compaction of a particular level isspecified for the unsupported and curving segment of the free-spacepath, processor 36 may estimate the segment's stiffness and/or strength(e.g., calculate an Area of Moment of Inertia I_(y) and a Minimum AreaMoment of Inertia I_(min) based on the Effective Modulus of ElasticityE_(avg) for the segment—Step 534), and then compare the stiffness and/orstrength to a stiffness and/or strength required to resist deviationfrom the planned location during compaction (Step 536). For example,when the Minimum Area Moment of Inertia is less than or equal to theArea of Moment of Inertia, structure 12 may be determined to beadequately stiff and/or strong, and no bracing or supports for thefree-space path may be required. However, when the Minimum Area Momentof Inertia is greater than the Area Moment of Inertia, processor 36 maygenerate bracing or support fabrication code associated with theunsupported segment of the free-space path (Step 538). Returning to Step530, any time that the radius of curvature of a given path is less thanthe minimum threshold, control may proceed directly to Step 538 forgeneration of bracing or support fabrication code.

In some embodiments, the paths generated at Steps 506, 508, and/or 522described above may require the use of multiple different nozzle modules24. For example, larger planes may include a single path fabricatedusing ribbon material, while smaller planes and/or paths within the sameplan may require single-track material. In these instances, nozzlemodule 24B (referring to FIG. 1) may need to be swapped out for nozzlemodule 24A in order for the paths to fabricated as planned In thisexample, processor 36 may be configured to determine the need forswapping of nozzle modules 24 (e.g., based on comparisons of sizes,locations, orientations, fiber types, etc. of planned paths with knowncapabilities of nozzle modules 24) (Step 540), and selectively generatecorresponding code for the swap (e.g., for automated swapping and/or forpausing and allowing of manual swapping—Step 542).

It is also contemplated that, rather than swapping one nozzle module 24for another nozzle module 24 connected to the same support 18, multiplenozzle modules 24 may be used at the same time. For example, processor36 could be connected to multiple machines 14 and, instead of callingfor nozzle module swapping to fabricate different paths and/or layers ofstructure 12, processor 36 could instead selectively assign differentmachines 14 to fabricate particular paths and/or layers of the samestructure 12. In this example, processor 36 may track the operation(e.g., location) of each nozzle module 24, and coordinate operations toavoid collisions and/or to cooperatively complete fabrication of aparticular feature. During this cooperative fabrication, the variousmachines 14 could be identical; have different supports 18, heads 20,and/or nozzle modules 24; and/or have different purposes and assignedtasks. For example, a first machine 14 may be a primary path generatingmachine, while a second machine 14 may be an outlier critical pointmachine, while a third machine 14 may be a repair or splicing machine,while a fourth machine 14 could be a post-processing machine, etc. Othermachine configurations may also be possible, and the same processor 36or communicatively coupled processors 36 could be used to control thedifferent machines 14.

When processor 36 determines that compaction, ultrasonics, or anotherauxiliary fabrication process is specified for a given segment of anypath, processor 36 may generate the corresponding code at any timeduring execution of the Pathing Module (Steps 544 and 546). Similarly,when processor 36 determines that post-processing (e.g., machining,coating, painting, cleaning, etc.) is specified for a given segment ofany path, processor 36 may generate the corresponding code at any timeduring execution of the Pathing Module (Steps 548 and 550).

Returning to the System Check Module shown in FIG. 6, processor 36 mayimplement a procedure to help ensure that machine 14 is ready to executethe selected plan and fabricate the selected design of structure 12.This procedure may include a number of different steps, which may beimplemented in any desired order. One of these steps may includedetermining if the particular nozzle module 24 required to produce thedesign is currently connected to head 20 (Step 600). In one embodiment,this determination may be made, for example, based at least in part oninput from the user that is indicative of the identity of the connectednozzle module 24. In another embodiment, processor 36 may automaticallydetect (e.g., based on captured images, signals, settings, detectedparameters, etc. generated by one or more of input devices ofperipherals 40A) the currently connected nozzle module 24 and comparethe detected nozzle module 24 to the required nozzle module 24. If thecurrently connected nozzle module 24 is not the required nozzle module24, processor 36 may display an error signal to the user (e.g., viadisplay 34), thereby prompting the user to swap out the current nozzlemodule 24 for the correct nozzle module 24 (Step 605). Alternatively,processor 36 may automatically swap out the current nozzle module 24.This may be accomplished, for example, by commanding support 18 (i.e.,by commanding actuators, motors, and/or other output devices ofperipherals 40B associated with support 18) to move head 20 to a droplocation, commanding release of the currently connected nozzle module24, commanding support 18 to move head 20 to a pickup location, andcommanding engagement of support 18 with the required nozzle module 24.When processor 36 determines at Step 600 that the correct nozzle module24 is connected to head 20, Step 605 may be omitted.

Once the correct nozzle module 24 is connected to head 20, processor 36may determine if the corresponding nozzle tip is clear of obstructions(Step 610). This may be accomplished, for example, by receipt of visualconfirmation by a user, by automated visual or vibratory confirmation(e.g., via one or more input devices of peripherals 40A), and/or byimplementing a specific nozzle tip test. The nozzle tip test may includecommanding a test amount of matrix to be discharged from the nozzle tip(e.g., by causing head 20 to move away from anchor point 32 by aparticular distance), monitoring a corresponding flow rate of matrix(e.g., a level change of matrix in reservoir 26), and comparing themonitored flow rate to an expected flow rate (i.e., a rate calculated asa function of the commanded movement distance, a known nozzle openingarea, a cross-sectional area of an associated fibers, and a knownviscosity of the matrix). If the monitored rate is significantly lessthan (e.g., 90% or less of) the expected flow rate, the nozzle tip maybe considered at least partially clogged. When this occurs, processor 36may display an error signal to the user (e.g., via display 34), therebyprompting the user to swap out the current nozzle module 24 for anothersimilar nozzle module 24 and/or to implement a clearing process (Step615). Processor 36 may alternatively implement the swap and/or clearingprocess automatically, if desired. When processor 36 determines that thenozzle tip is adequately clear of obstruction, Step 615 may be omitted.

Another step in the procedure performed by the System Check Module mayinclude determining if a sufficient supply of matrix and/or fiber iscurrently provided to head 20 (Step 620). In one embodiment, thisdetermination may be made, for example, based at least in part on inputfrom the user that is indicative of an amount of matrix and/or fiber in,on or otherwise being passed to head 20. Specifically, processor 36 maycompare this amount with the amount stipulated at Step 302 to determineif at least 25% more than required to make structure 12 is currentlyavailable. It is contemplated that processor 36 may additionally oralternatively track supply and usage of matrix and/or fiber (e.g., viaone or more input and/or output devices of peripherals 40), and comparean amount consumed with an amount supplied and the amount required todetermine if at least 25% more than required to make structure 12 iscurrently available. When less than 125% of the required amount ofmatrix and/or fiber is currently available, processor 36 may display anerror signal to the user (e.g., via display 34), thereby prompting theuser to refill the corresponding supply of matrix and/or fiber (Step625). Processor 36 may alternatively implement an automatedreplenishment process, if desired. When processor 36 determines thatsufficient material is available, Step 625 may be omitted.

It is contemplated that, in some embodiments, the automatedreplenishment process may involve more than just providing additionalmaterial to head 20. For example, there may be instances where asignificant amount of fiber is available to head 20, but still notenough to complete structure 12. In these instances, processor 36 maynot simply supply more fiber to head 20. Instead, Step 625 mayadditionally include planning of a splice location at a particularprogress point within structure 12 (e.g., at a feature or trajectorychange), and thereafter (e.g., during completion of Steps 336 and338—referring to FIG. 3) selectively activating an input device ofperipherals 40A (e.g., the splicer) to dynamically swap out a firstsupply of fiber with a replacement supply of the same or a differentfiber.

Another step in the procedure performed by the System Check Module mayinclude determining if environmental factors associated with theintended-use matrix, fiber, and/or nozzle module 24 are within acorresponding tolerance window (Step 630). In one embodiment, thisdetermination may be made, for example, based at least in part on inputfrom the user that is indicative of what matrix, fiber, and/or nozzlemodule 24 are in use and/or what environmental factors should be used inassociation with these elements. Specifically, processor 36 may comparethis information with monitored conditions (e.g., temperature, humidity,build area gas composition, etc.—monitored via one or more input devicesof peripherals 40A) to determine if the environment of machine 14 isconducive to structure fabrication. It is contemplated that processor 36may additionally or alternatively have stored in memory relationshipsbetween different matrixes, fibers, and/or nozzle modules 24, andautomatically reference this information during the above-describedcomparison. When current environmental factors are not within acceptableranges for producing a given design of structure 12 with a particularmatrix, fiber, and/or nozzle module 24, processor 36 may display anerror signal to the user (e.g., via display 34), thereby prompting theuser to adjust the environmental factors (Step 635). Processor 36 mayalternatively implement an automated adjustment process, if desired.When processor 36 determines that the environmental factors areacceptable, Step 635 may be omitted.

Another step in the procedure performed by the System Check Module mayinclude determining if output devices of peripherals 40 (e.g., cureenhancer 22, optics 31, support actuators, sensors, actuators, motors,etc.) are fully functional and within desired operating ranges (Step640). In one embodiment, this determination may be made, for example,based at least in part on input from the user that is indicative ofknown functionalities of particular components. It is contemplated thatprocessor 36 may additionally or alternatively have stored in memoryoperational statuses and/or acceptable operating ranges of particularcomponents, and automatically reference this information within sensorydata and/or feedback provided via peripherals 40. When one or morecomponents of machine 14 are not fully functional or functional withinacceptable ranges, processor 36 may display an error signal to the user(e.g., via display 34), thereby prompting the user to adjust (e.g.,service or replace) the corresponding components (Step 645). Processor36 may alternatively implement an automated adjustment process, ifdesired. When processor 36 determines that all components of machine 14are fully functional, Step 645 may be omitted.

Returning to the Setup Module shown in FIG. 7, processor 36 mayimplement a procedure to set up machine 14 according to the selectedplan for fabricating the selected design of structure 12. This proceduremay include a number of different steps, which may be implemented in anydesired order. One of these steps may include determining if theselected plan calls use of a single-track material (e.g., materialhaving one or more continuous fibers with a generally circularcross-section and a closed center), ribbon or sheet material (e.g.,material having one or more continuous fibers with a generallyrectangular cross-section), or tubular material (e.g., material havingone or more continuous fibers with a generally circular cross-sectionand an open center) (Step 700). When the fabrication plan calls for theuse of single-track material, processor 36 may implement automaticfiber-threading of nozzle module 24 or allow for manual fiber-threading(Step 705). Automated threading may be implemented, for example, byprocessor 36 selectively activating one or more of peripherals 40 tocause an amount of coated reinforcement to be feed into nozzle module24, at least partially hardened (e.g., via one or more internal cureenhancers 22) and/or shaped (e.g., via a needle-shaped die), and thenadvanced through the tip of nozzle module 24. Once the required fibershave been threaded through nozzle module 24, processor 36 mayselectively activate any other output devices of peripherals 40Brequired during material discharge (Step 710). These peripherals 40B mayinclude, for example, matrix supply jets, actuators and/or motorsassociated with movement of support 18, cure enhancers 22, optics 31,etc.

Returning to Step 700, when processor 36 determines that the fabricationplan calls for use of tubular material, processor 36 may determine ifthe material is prefabricated (e.g., pre-woven into a tubular structureprior to introduction into head 20) or will be woven in-situ (Step 715).When the tubular material is prefabricated, processor 36 may implementautomatic fiber-loading of head 20 or allow for manual fiber-loading(Step 720). Automated loading may be implemented, for example, byprocessor 36 selectively activating one or more output devices ofperipherals 40B to cause an amount of the prefabricated material to bedrawn or pushed (e.g., via one or more feed rollers) into matrixreservoir 26 over a centrally located guide rod (not shown) andcompressed axially, before attachment of nozzle module 24 to matrixreservoir 26. A lower end of the material may protrude through nozzlemodule 24 at this time. Once the required fibers have been threadedthrough nozzle module 24, control may proceed to Step 710 describedabove.

When the tubular material is to be woven in-situ, processor 36 mayimplement automatic fiber-threading of any number of moveable (e.g.,oscillating and/or rotating) fiber guides within head 20 or allow formanual fiber-threading of the guides (Step 725). Automated threading maybe implemented in much the same way described above with respect to Step710, and then the fibers may be pushed radially outward around adiverter located at a mouth of nozzle module 24. Once the requiredfibers have been threaded through the fiber guides and around thediverter, movement of the fiber guides may be initiated to start weavingof the fibers (Step 730), and control may proceed to Step 710 describedabove.

Returning to Step 700, when processor 36 determines that the fabricationplan calls for use of ribbon or sheet material, processor 36 maydetermine if the material is prefabricated (e.g., pre-woven into arectangular structure prior to introduction into head 20) or will bewoven in-situ (Step 735). When the rectangular material isprefabricated, processor 36 may implement automatic fiber-threading ofnozzle module 24 or allow for manual fiber-threading (Step 740).Automated threading may be implemented, for example, by processor 36selectively activating one or more output devices of peripherals 40B tocause a supply of the prefabricated material to be drawn or pushed(e.g., via one or more feed rollers in response to feedback from one ormore rotary encoders) through matrix reservoir 26 and out through a tipof nozzle module 24. A lower end of the material may protrude throughthe tip of nozzle module 24 at this time. Once the required fibers havebeen threaded through nozzle module 24, control may proceed to Step 710described above.

When the tubular material is to be woven in-situ, processor 36 mayimplement automatic fiber-threading of any number of moveable (e.g.,oscillating and/or rotating) fiber guides within head 20 or allow formanual fiber-threading of the guides (Step 745). Automated threading maybe implemented in much the same way described above with respect to Step710, and then the fibers may be pushed axially through one or moreadjacent channels located at the mouth of nozzle module 24. Once therequired fibers have been threaded through the fiber guides and outnozzle module 24, movement of the fiber guides may be initiated to startweaving of the fibers (Step 750), and control may proceed to Step 710described above.

As part of setting up machine 14 to discharge composite material,processor 36 may determine if compaction of the material would bebeneficial after the discharge (Step 755). This determination may bemade in any number of different ways. For example, the determination maybe made based on stipulations of the fabrication plan required to meetassociated strength or stiffness requirements. Alternatively, thedetermination of Step 755 may be made based on comparison of otherfabrication conditions (e.g., steps between overlapping layers, materialdensities, material types, cure levels, etc.) with one or moreconditions stored in memory. In yet another embodiment, thedetermination may be made based on observations (e.g., based on scannedimages generated via one or more input devices of peripherals 40A thatcorrespond with a rough surface) of discharged material.

Regardless of how the determination of Step 755 is made, processor 36may need to determine how the compaction should be applied at any givenlocation of structure 14. For example, processor 36 may determine if thecompaction is required on a layer of material discharged into free spaceor only a layer that overlaps another layer (e.g., a previouslydischarged layer, an anchor surface, etc.) (Step 760). Thisdetermination may be made, for example, based on stipulations of thefabrication plan and/or scanned images of the discharged materialshowing included or a lack of support). When the material requiringcompaction is discharged into free space, a lower level of compactionmay be implemented by processor 36 (e.g., via selective activation ofone or more output devices of peripherals 40B) (Step 765). In oneembodiment, this lower level of compaction may be a level that providesdesired compaction without causing deviation of the material from adesired trajectory. For example, this lower level of compaction may beabout 0-1 psi. When the material requiring compaction is discharged ontop of another layer, a higher level of compaction may be implemented byprocessor 36 (Step 770). In one embodiment, this higher level ofcompaction may be about 1 psi or greater and oriented in a directionthrough the material toward the support located at an opposing side ofthe material.

In the disclosed embodiments, the varying levels of compaction may beprovided by selectively adjusting a negative offset distance that theassociated output device of peripherals 40B push into the dischargedpath of composite material. In other embodiments, the varying levels ofcompaction may be provided by adjusting a force of the associated outputdevice of peripherals 40B (e.g., by adjusting a level of electrical orhydraulic power provided to the output device). In yet otherembodiments, a first output device of peripherals 40B may be selectivelyactivated provide the lower level of compaction, while a second outputdevice of peripherals 40B may be selectively activated to provide thehigher level of compaction. In some embodiments, for example when thelayer of material being compacted is non-planar (e.g., curved),processor 36 may need to regulate motion of an associated compactingdevice (e.g., of a roller or shoe, via selective activation of one ormore output devices of peripherals 40B) to follow the surface topology.

At any point during operation of the Setup Module, processor 36 maydetermine if ultrasonics (i.e., ultrasonic vibrations induced withinhead 20) would be beneficial (Step 775). This determination may be madein any number of different ways. For example, the determination may bemade based on stipulations of the fabrication plan. Alternatively, thedetermination of Step 775 may be made based on comparison of otherfabrication conditions (e.g., steps between overlapping layers, materialdensities and/or viscosities, material types, cure levels, etc.) withone or more conditions stored in memory. In yet another embodiment, thedetermination may be made based on observations (e.g., scanned images)of discharged material. Use of ultrasonics may improve fiber-to-fiberadhesion, reduce bubble formation within the matrix, and/or improvefiber impregnation. When processor 36 determines that ultrasonics may bebeneficial, processor 36 may selectively activate one or more outputdevices of peripherals 40B to generate corresponding ultrasonicvibrations within head 20 during discharge of composite material.

Returning to the Anchoring Module shown in FIG. 8, processor 36 mayimplement a procedure to cause machine 14 to secure a starting end of afirst path of material to anchor point 32 (referring to FIG. 1), beforecausing the material to be pulled from nozzle module 24 according to theselected plan for fabricating the selected design of structure 12. Thisprocedure may include a number of different steps, which may beimplemented in any desired order. One of these steps may includedetermining if anchor point 32 exists and the location(s) (e.g., thecoordinates) of any existing anchor points 32 (Step 800). In someembodiments, if no pre-existing anchor points 32 exist, processor 36 mayneed to first cause anchor points 32 to be created. Processor 36 maydetermine if any anchor points 32 exist based on manual input, based onthe fabrication plan, and/or based on scanning of a print area (e.g.,via one or more peripherals 40A).

When one or more anchor points 32 exist (and when anchoring isrequired), processor 36 may determine if nozzle module 24 is at ananchor point location (Step 810). Processor 36 may selectively activateone or more output devices of peripherals 40B to move nozzle module 24to the anchor point location, if necessary (Step 820). Once nozzlemodule 24 is determined to be at the anchor point location, processor 36may determine if the corresponding anchor point 32 is a hard surface(e.g., fully cured or otherwise stable surface) or a previouslydischarged (and still curing or unstable) surface (Step 830). Thisdetermination may be made, for example, based on a tracked amount oftime elapsed since fabrication of the anchor point 24. When anchor point32 is a previously discharged surface, processor 36 may cause a normalor baseline ratio of matrix-to-fiber to be discharged at the anchorpoint location (Step 840). This ratio may be achieved by moving a tipend of nozzle module 24 across the surface of anchor point 32 at anormal or baseline rate, such that the matrix deposited on anchor point32 is proportional to an amount of fiber pulled from nozzle module 24.However, when anchor point 32 is a hard surface, processor 36 may causea higher ratio of matrix-to-fiber to be discharged at the anchor pointlocation (Step 850). This ratio may be achieved by the tip end of nozzlemodule 24 dwelling for a period of time at anchor point 32 and/or movingthe tip across anchor point 32 at a slower rate, such that a greateramount of matrix is pushed out, leaks out, or otherwise is dischargedout of the tip end for a given length of fiber being pulled out. Theincreased amount of matrix may improve adhesion to the hard surface.Cure enhancers 22 may be selectively activated by processor 36 duringcompletion of Steps 840 and 850.

In some embodiments, the hard surface-type anchor points 32 may beequipped with one or more embedded electro-mechanism (e.g., energysources, compaction sources, vibratory sources, magnetic repulsion orattraction sources, and/or other output devices of peripherals 40B). Inthese embodiments, during anchoring to the hard surface-type anchorpoints 32, processor 36 may be configured to selectively cause theseelectro-mechanisms to activate in order to improve anchoring.

Returning to the Discharge Module of FIG. 9, after anchoring of a pathof material, processor 36 may cause the material to be discharged(pulled and/or pushed) from nozzle module 24 (Step 900). This mayinvolve, among other things, activating output devices of peripherals40B associated with support 18 to move nozzle module 24 along atrajectory of the path at a specified speed, and regulating nozzlemodule 24 (e.g., one or more output devices of peripherals 40B inside ofnozzle module 24) to release the associated fibers with a specifiedtension. In addition, processor 36 may selectively activate the outputdevices of peripherals 40B to compact the discharging material, toirradiate the discharging material, and/or to vibrate nozzle module 24and/or the discharging material according to parameters specified for agiven location within the path.

During the discharge of material from nozzle module 24, the progress ofpath fabrication may be monitored (Step 905). This monitoring mayinclude, for example, detecting a current position of nozzle module 24,and comparing the current position to trajectory changes planned for thepath (Step 910). When processor 36 determines that no significanttrajectory changes (e.g., angular rate changes greater than a thresholdangle rate) are planned for the current path, processor 36 may determineif the current path is complete (Step 915) and cycle back through Steps900-915 until path completion.

However, when processor 36 determines at Step 910 that a significanttrajectory change (e.g., a corner) is planned for the current path,processor 36 may determine how close the current location of nozzlemodule 24 (e.g., the tip of nozzle module 24) is to the trajectorychange location (Step 920). For example, processor 36 may determine if adistance from a current location of the nozzle tip to the trajectorychange is about equal to a distance from the nozzle tip to a leadingedge of an energy area (an area of irradiance generated by cureenhancer(s) 22) that at least partially surrounds the nozzle tip. Whenthese distances are not about equal (e.g. when the nozzle tip is not yetsufficiently near the corner location), control may return to Step 900.

However, when the tip of nozzle module 24 is close to the cornerlocation (e.g., when the distance from the current location of thenozzle tip to the trajectory change is about equal to the distance fromthe nozzle tip to the leading edge of the energy area), processor 36 maydetermine if the corner is a sharp corner (e.g., if the angle rate ofthe trajectory change is greater than a threshold rate) (Step 925). Whenprocessor 36 determines that the trajectory change is not a sharp corner(e.g., when the angle rate of the trajectory change is less than thethreshold rate), processor 36 may deactivate cure enhancer(s) 22, suchthat curing of subsequently discharged material is temporarily inhibited(or at least not enhanced) (Step 930).

Processor 36 may then control support 18 and/or head 20 (e.g., one ormore output devices of peripherals 40B associated with support 18 and/orhead 20) to continue discharging material past the trajectory changelocation (e.g., continuing in the original trajectory), until a desiredlength of material has been pulled from nozzle module 24 (Step 335).This desired length may be, for example, about equal to a distance fromthe tip of nozzle module 24 to a trailing edge of the energy area. Inone embodiment, processor 36 may implement a ramp down in nozzle travelspeed during the discharge of the desired length of material (Step 940).

After the desired length of material has been discharged along theoriginal trajectory, processor 36 may cause support 18 to move head 20and nozzle module 24 through the trajectory change to a new trajectory(e.g., to pivot nozzle module 24 through a specific angle around thecorner, rotating nozzle module 24 if necessary to maintain fiberintegrity), dragging the desired length of uncured material through anarc behind nozzle module 24 (Step 945). Processor 36 may then reactivatecure enhancer(s) 22 to cure the desired length of discharged material atits new location along the new trajectory (Step 950), and then rampnozzle travel speeds back up to speeds previously planned for the givenpath of material (Step 955). In some embodiments, processor 36 maytemporarily bump up the speed of nozzle module 24 immediately after cureenhancer(s) 2 have been activated (e.g., to a level higher than planned,before returning to the planned level) to generate a small tug on thematerial that functions to cast off excess matrix and/or free any snagsthat may have been created during the trajectory transition. Control maythen progress to Step 915 described above.

Returning to Step 925, when processor 36 determines that the trajectorychange is a sharp corner, processor 36 may deactivate cure enhancer(s)22 (Step 960) and ramp down travel speed going into the corner (Step965). Processor 36 may then cause support 18 to move nozzle module 24through a first portion (e.g., a first ½) of the trajectory change,rotating nozzle module 24 during the movement in order to maintain fiberintegrity (if necessary) (Step 970). It should be noted that thistrajectory change may generally be accomplished within the same generalplane. Processor 36 may then cause support 18 to move nozzle module 24 astep in a positive normal direction relative to the plane of thetrajectory change (Step 975), followed by a step in a negative normaldirection (Step 980). These movements may function to create slack inthe associated fibers, thereby reducing snags and/or excessive forces onthe pre-corner segment of the path that is already at least partiallycured. Processor 36 may then cause support 18 to ramp down the travelspeed of nozzle module 24 once more (Step 985), and then to causesupport 18 to move nozzle module 24 through a remaining portion (e.g., asecond′) of the trajectory change (Step 990). Control may then passthrough Steps 950, 955, and 915 described above.

At any point during discharge of material from nozzle module 24,processor 36 may execute the Quality Control Module shown in FIG. 10.This may include, among other things, processor 36 monitoring materialdischarge from nozzle module 24 (e.g., via any one or more of inputdevices of peripherals 40A, such as an optical scanner that generatesimages of the discharging material) (Step 1000), and comparing alocation and/or orientation of discharged material (e.g., an axis of theassociated fiber(s) and/or a cross-sectional shape and size of thematrix coating on the fiber(s)) to a planned location and/or orientation(Step 1005). For example, processor 36 may compare the location and/ororientation to a first or wider tolerance zone positioned about theplanned location and/or orientation. When it is determined that thedischarged material falls outside of the first tolerance zone, processor36 may cause an error to be shown on display 34 (referring to FIG. 1),and prompt for manual interruption of or automatically interrupt (e.g.,abort) the current fabrication process (Step 1010). In this situation,fabrication of structure 12 may have failed.

However, when processor 36 determines at step 1005 that the dischargedmaterial is within the first tolerance zone, processor 36 may comparethe location and/or orientation of the discharged material to a secondor narrower tolerance zone positioned about the planned location and/ororientation (Step 1015). In this situation, even though some positiondeviation may have occurred, the deviation is still acceptable and canbe corrected. Accordingly, processor 36 may automatically adjustoperation of head 20 (Step 1020), and control may return to Step 1000.For example, processor 36 may adjust the trajectory of nozzle module 24(e.g., via activation of one or more output devices of peripherals 40Bassociated with support 18 and/or head 20, for example to press adjacentpaths closer together and/or to build up around the deviation). Inanother example, processor 36 may adjust a matrix discharge rate, suchthat a cross-sectional size and/or shape of the matrix surrounding thefiber may be altered. In yet another example, processor 36 may adjust acure rate of the matrix material (e.g., increase or decrease the curerate, by adjusting a position, orientation, and/or intensity of cureenhancers 22). Adjusting the cure rate may affect, for example, anamount of slump occurring before hardening and/or an amount ofcompaction that is possible prior to hardening.

At any point during execution of the Pathing Module, processor 36 maycompare a current tension with the fibers of a discharged path with atension specified in the path plan (Step 1025). When the current tensionis significantly different from the specified tension (e.g., by at leasta threshold amount), processor 36 may determine if one or more of thefibers has broken (Step 1030). In one embodiment, breakage of the fibersmay be exhibited by a significant and/or sudden drop in fiber tension,as measured by one or more input devices of peripherals 40A. In anotherembodiment, breakage of the fibers may be determined by comparing atravel distance of nozzle module 24 (e.g., as exhibited via one or moreinput devices of peripherals 40A, such as rotary encoders, located atthe tip of nozzle module 24) with a length of fibers supplied to nozzlemodule 24 (e.g., as exhibited via one or more input devices ofperipherals 40A, such as feed rollers, located at a fiber inlet ofnozzle module 24). When the travel distance is significantly greaterthan the supplied length of fibers, processor 36 may consider the fibersto have broken.

When processor 36 determines that the fibers in the current path areunbroken, and that the tension level in the fibers is simply not withinspecifications of the fabrication plan, processor 36 may automaticallyadjust the tension level (Step 1035). The tension level in the fibersmay be adjusted in any number of different ways. For example, a travelspeed of nozzle module 24 may be increased for a given supply rate offibers to increase the tension level, and vice versa. In anotherexample, the supply rate may be slowed relative to a given travel speed.One or more friction actuators (e.g., rollers inside of head 20) orother output devices of peripherals 40B may also or alternatively beselectively adjusted to thereby adjust the tension level of the fibers.Control may return from Step 1035 to Step 1000.

When processor 36 determines that one or more of the fibers in thecurrent path have broken, processor 36 may cause an error to be shown ondisplay 34 (referring to FIG. 1), and prompt for manual interruption ofor automatically interrupt the current fabrication process (Step 1040).In this situation, fabrication of structure 12 may have failed.

At any point during execution of the Pathing Module, processor 36 maycompare an energy continuity (e.g., tensile continuity, electricalcontinuity, optical continuity, internal pressure continuity, etc.) ofthe fibers (e.g., electrical leads, fiber optics, gas lines, etc.) of adischarged path with a continuity specified in the fabrication plan(Step 1045). For example, processor 36 may selectively activate anenergy source or other output device of peripherals 40B located at oneend of a current path (e.g., at anchor point 32—referring to FIG. 1),while simultaneously monitoring signals generated by a correspondingcontinuity sensor or other input device of peripherals 40A located at anopposing end of the current path (e.g. at a fiber spool). Any loss ofcontinuity (e.g., due to fiber cracks or breaks) may be exhibited in theform of low tension, high electrical resistance, low lighttransmittance, low pressure, etc. When this occurs, processor 36 maycause an error to be shown on display 34 (referring to FIG. 1), andprompt for manual interruption of or automatically interrupt the currentfabrication process (Step 1050). In this situation, fabrication ofstructure 12 may have failed.

It may be possible in some configurations of machine 14 (e.g., infiber-fed configurations), for fiber to bunch up inside of and clog head20. Processor 36 may monitor for this condition, by comparing a feedrate of the fiber to a discharge rate (e.g., to a travel rate of nozzlemodule 24) (Step 1055). When the feed rate exceeds the discharge rate bya threshold amount, processor 36 may cause an error to be shown ondisplay 34 (referring to FIG. 1), and prompt for manual interruption ofor automatically interrupt the current fabrication process (Step 1060).In this situation, fabrication of structure 12 may have failed.

At any point during discharge of material from nozzle module 24,processor 36 may execute the Splicing/Severing Module shown in FIG. 11.For example, this module may be executed between fabrication ofsequential paths, between fabrication of sequential layers, duringswapping of nozzle modules 24 and/or fibers, when a fiber is broken orotherwise determined to be discontinuous, etc. During execution of thismodule, processor 36 may cause support 18 to move head 20 to thelocation of the required splice and/or severance (if head 20 is notalready at the required location) (Step 1100). Processor 36 may thendetermine if splicing or severing is required (Step 1105). This may bedetermined in any number of different ways, for example based on thefabrication plan and a progression of a current path, based on an errorcode, based on manual input, etc. When splicing is required, processor36 may activate one or more output devices of peripherals 40B to advancea cutter into and sever any existing fibers that are passing throughnozzle module 24 (Step 1110), and then activate one or more other outputdevices of peripherals 40B to cause an end of a replacement fiber tooverlap an end of the severed fiber (Step 1115). In some embodiments,both ends may already by impregnated with a splicing matrix. In otherembodiments, however, the fiber ends to be spliced may be impregnatedwith the splicing matrix at Step 1115, for example via one or moreoutput devices of peripherals 40B. Processor 36 may thereafter activateone or more other output devices of peripherals 40B to cause a die toclamp down over the impregnated fiber ends, pressing the ends together(1120). Internal cure enhancers (or other output devices of peripherals40B) may then be activated to cure the splicing matrix, thereby bondingthe ends to each other (Step 1125). Once processor 36 determines thatthe curing of Step 1125 is complete (e.g., based on an elapsed period oftime, a temperature, etc.), processor 36 may cause the correspondingoutput devices of peripherals 40B to open the die and release the bondedends.

Returning to Step 1105, when severing is required, processor 36 maydetermine if the fibers trailing from the tip of nozzle module 24 needto be grasped prior to severing (Step 1140). This determination may bemade based on, among other things, characteristics of the fiber(s),characteristics of the matrix, and characteristics of the cutter. Forexample, a smaller fiber that is fully encased in a brittle matrix maynot need to be grasped when cut with a laser-type cutter. However, alarger fiber that is encased in a more flexible matrix may need to begrasped prior to cutting via a pivoting blade. When grasping isrequired, processor 36 may energize the corresponding output devices ofperipherals 40B (Step 1145), and selectively activate the correspondingcutter (e.g., energize an ultrasonic cutter to a desired frequency,energy a laser to a desired intensity, and/or extend or rotate a blade)(Step 1150). Processor 36 may monitor the severing (e.g., via one ormore of input devices of peripherals 40A), and loop back through Step1150 until severing is complete.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the disclosed systems andmethods. Other embodiments will be apparent to those skilled in the artfrom consideration of the specification and practice of the disclosedsystems and methods. It is intended that the specification and examplesbe considered as exemplary only, with a true scope being indicated bythe following claims and their equivalents.

What is claimed is:
 1. A system for additively manufacturing astructure, comprising: an additive manufacturing machine; a memoryhaving computer-executable instructions stored thereon; and a processorconfigured to execute the computer-executable instructions to: determinea characteristic of an existing point to be used as an anchor for a pathof composite material discharged by the additive manufacturing machine;and selectively cause the additive manufacturing machine to dischargethe path of composite material with a variable ratio of matrix-to-fiberat the existing point that is based on the characteristic.
 2. The systemof claim 1, wherein the characteristic is a stability of the existingpoint.
 3. The system of claim 2, wherein the processor is configured toexecute the computer-executable instructions to determine the stabilityof the existing point based on an amount of time elapsed sincefabrication of the existing point.
 4. The system of claim 3, wherein theprocessor is further configured to execute the computer-executableinstructions to: determine a plan for fabrication of the structure withthe composite material; determine locations of existing points; andselectively cause the additive manufacturing machine to fabricate theexisting point prior to discharge of the path when the existing pointsdo not correspond with the plan.
 5. The system of claim 2, wherein: whenthe existing point is less than fully cured, the processor is configuredto execute the computer-executable instructions to cause the additivemanufacturing machine to discharge the path of composite material with abaseline ratio of matrix-to-fiber; and when the existing point is fullycured, the processor is configured to execute the computer-executableinstructions to cause the additive manufacturing machine to dischargethe path of composite material with a greater ratio of matrix-to-fiber.6. The system of claim 5, wherein the processor is configured to executethe computer-executable instructions to cause the additive manufacturingmachine to discharge the path of composite material with the greaterratio of matrix-to-fiber by at least one of pausing or slowing nozzlemovement of the additive manufacturing machine at the existing point. 7.The system of claim 6, wherein the processor is further configured toexecute the computer-executable instructions to: determine when thecomposite material is bonded to the existing point; and responsivelycause a nozzle of the additive manufacturing machine to move away fromthe existing point.
 8. The system of claim 7, wherein movement of thenozzle away from the existing point causes the composite material to bepulled from the nozzle.
 9. The system of claim 7, wherein the processoris further configured to execute the computer-executable instructions todetermine bonding of the composite material to the existing point basedon at least one of a number of cure enhancers included in the additivemanufacturing machine, an intensity of cure energy generated by the cureenhancers, and an exposure time of the composite material to the cureenergy.
 10. The system of claim 9, wherein the processor is furtherconfigured to execute the computer-executable instructions toselectively activate the cure enhancers while the composite material isbeing discharged onto the existing point.
 11. A method of fabricating astructure with an additive manufacturing machine, the method comprising:determining a characteristic of an existing point to be used as ananchor for a path of composite material discharged by the additivemanufacturing machine; and selectively causing the additivemanufacturing machine to discharge the path of composite material with avariable ratio of matrix-to-fiber at the existing point tha is based onthe characteristic.
 12. The method of claim 11, wherein thecharacteristic is a stability of the existing point.
 13. The method ofclaim 12, wherein determining the characteristic of the existing pointincludes determining the stability of the existing point based on anamount of time elapsed since fabrication of the existing point.
 14. Themethod of claim 13, further including: determining a plan forfabrication of the structure with the composite material; determininglocations of existing points; and selectively causing the additivemanufacturing machine to fabricate the existing point prior to dischargeof the path when the existing points do not correspond with the plan.15. The method of claim 12, wherein: when the existing point is lessthan fully cured, the method includes causing the additive manufacturingmachine to discharge the path of composite material with a baselineratio of matrix-to-fiber; and when the existing point is fully cured,the method includes causing the additive manufacturing machine todischarge the path of composite material with a greater ratio ofmatrix-to-fiber.
 16. The method of claim 15, wherein causing theadditive manufacturing machine to discharge the path of compositematerial with a greater ratio of matrix-to-fiber includes causing theadditive manufacturing machine to discharge the path of compositematerial with the greater ratio of matrix-to-fiber by at least one ofpausing or slowing nozzle movement of the additive manufacturing machineat the existing point.
 17. A non-transitory computer readable mediumcontaining computer-executable programming instructions for performing amethod of additively manufacturing a structure, the method comprising:determining a stability of an existing point to be used as an anchor fora path of composite material discharged by an additive manufacturingmachine; and selectively causing the additive manufacturing machine todischarge the path of composite material with a variable ratio ofmatrix-to-fiber at the existing point that is based on the stability.18. The non-transitory computer readable medium of claim 17, whereindetermining the stability of the existing point includes determining thestability of the existing point based on an amount of time elapsed sincefabrication of the existing point.
 19. The non-transitory computerreadable medium of claim 17, wherein the method further includes:determining a plan for fabrication of the structure with the compositematerial; determining locations of existing points; and selectivelycausing the additive manufacturing machine to fabricate the existingpoint prior to discharge of the path when the existing points do notcorrespond with the plan.
 20. The non-transitory computer readablemedium of claim 17, wherein: when the existing point is less than fullycured, the method includes causing the additive manufacturing machine todischarge the path of composite material with a baseline ratio ofmatrix-to-fiber; and when the existing point is fully cured, the methodincludes causing the additive manufacturing machine to discharge thepath of composite material with a greater ratio of matrix-to-fiber.